1. Field of the Invention
This invention generally relates to a reflection plate assembly. More specifically, the present invention relates to a heat gathering device having the reflection plate assembly for light gathering.
2. Background Information
Various types of devices have been suggested as devices for obtaining heat energy from sunlight through heat medium or for obtaining electric energy through solar battery. There is a device which has a reflection plate whose cross-section is a compound paraboloid, instead of a single paraboloid.
A typical conventional heat gathering device includes a reflection plate whose cross-section is a compound parabola, and a heat gathering tube. The compound parabola is a combination of a first single parabola and a second single parabola, which both have a same focus or focal point.
In an above described heat gathering device, the accuracy of the compound paraboloid surface of a reflection plate is crucial. Even a small inaccuracy of the compound paraboloid surface can result in a large decrease in the heat gathering efficiency. The reflection plate is typically made by applying several layers of coating on a sheet metal, e.g., depositing a specular surface thereon, and then forming the specular sheet metal into a compound paraboloid. Since the specular sheet is too thin to be used on a presswork device, the specular sheet metal is typically formed into the shape of the reflection plate by bending.
When the specular sheet metal is bent to form a compound paraboloid, it is difficult to maintain the accuracy of measurement. Although using a presswork device would improve the accuracy of the specular surface, it is difficult to use a presswork device on a specularized sheet metal. Coating the sheet metal with resin or thickening the sheet metal maintains the accuracy of the measurement. But increases cost and weight of the reflection plate.
In view of the above, there exists a need for a reflection plate assembly of a heat gathering device that overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.